Human skin is covered with the stratum corneum, which is a thin biological protective membrane. This stratum corneum exposed to the external world allows us to live in the dry atmosphere without losing water. The stratum corneum is thin and supple, and contributes to maintenance of healthy skin by preventing loss of body water. Healthy skin is generally said to have a water content of 10 to 20%.
However, aging, change of seasons, etc. may impair normal system for controlling the water content in the stratum corneum, causing rough skin or serious skin problems. Conventionally, in order to improve the water retention capacity of the stratum corneum and prevent rough skin, polyhydric alcohols such as glycerol, hyaluronic acid, chondroitin, collagen, a mucopolysaccharide, etc. have been used as a moisturizer (see JP-A No. 2001-89381, JP-A No. 2002-145753 and JP-A No. 2005-314402). In particular, a polyhydric alcohol, which has also antiproliferative action on bacteria and has less skin irritation, is widely used as a moisturizing component in cosmetics. However, the moisturizing action of each of the above components, such as polyhydric alcohol, hyaluronic acid, chondroitin, collagen, a mucopolysaccharide, etc. is relatively of short duration, and is not continuously beneficial in improvement or prevention of rough skin. In addition, a feeling of greasiness or hot flashes brought by blending a large quantity of polyhydric alcohol, a mucopolysaccharide, etc. into a skin external agent has also been pointed out as a problem. Cosmetics containing saccharides such as panose for the purpose of solving these problems have been known (see JP-A No. 6-219935 and JP-A No. 2005-89356).